Über Tetraaryl-methan-analoga in der gruppe 14

The title compounds have been synthesized by Li and Grignard reactions. The crystal structure of Ph3Si-p-Tol has been determined. The substitution of only one phenyl by one p-tolyl group causes only a slight deviation from the ideal S4 symmetry of Ph4Si. Gradual replacement of phenyl by p-tolyl groups leads to increasing low field shifts for all 13C(ipso) atoms. The substitution of the first phenyl group by p-tolyl in Ph4Si and Ph4Sn results in a high field shift both for δ(29Si) (−0.3 ppm) and for δ(119Sn) (−1 ppm). Further replacement shows nearly linear dependencies (Δδ(29Si) = −0.1 ppm, Δδ(119Sn) = + 1.5 ppm per p-tolyl group).